A Damn Fine Ass
by MissDizzyD
Summary: Stiles would tell people that their relationship morphed seamlessly from I'll-Tolerate-Your-Presence-When-There-Is-A-Disast er to Stay-With-Me-No-Matter-What-Happens. Gradual change, he'd mutter, and only when directly asked. However, the truth is almost always completely different to what comes out of Stiles' mouth.


_For Siobhan, whose birthday is soon. Here's hoping for a Derek, eh?_

_Dizzy xx_

**A Damn Fine Ass**

Stiles would always say that he wasn't sure when it started. He'd tell people that their relationship morphed seamlessly from _I'll-Tolerate-Your-Presence-When-There-Is-A-Disast er_ to _Stay-With-Me-No-Matter-What-Happens_. Gradual change, he'd mutter, and only when directly asked.

However, the truth is almost always completely different to what comes out of Stiles' mouth. He is the king of dishonesty, the prince of falsities and the lord of half-truths, for half-truths is exactly what holds Stiles' life together. So instead of a series of small shifts between him and Derek that eventually lead to what they have now, there was a specific moment, a _huge_ moment. And that moment was Stiles' 18th birthday, when everyone's favourite Alpha showed up at the teenager's front door bearing gifts more spectacular than anyone could expect.

...

His birthday had been disappointing so far. The Sherriff had been taking double shifts so wasn't home until Stiles had left for school and other than a quick text from his dad wishing him a happy birthday, Stiles had heard nothing from anyone. Scott normally picked him up and drove him to school on his birthday, as had been the deal since they got cars, but after 10 minutes of waiting for his best friend, Stiles got fed up and jumped into his jeep muttering about unreliable friends.

Once in the school parking lot he knew for sure that today was going to be bad – like the type of bad that normally has him all jittery and twitchy and wanting to run mile after mile in any direction – something in the air just wasn't quite right.

His mood darkens even further when Scott pulls up to his right with Allison in the passenger seat of his car. Not that he's jealous, but it might have been nice to get a heads up. He suddenly imagines Allison as Vicki Vale, stealing his Batman's attention. Stiles knows he has to get out of his jeep, even though he seriously doesn't want to right now, so he sighs hugely and opens his door, wondering how cathartic it would feel to smash it right into Scott's car.

"Hey, dude, what's up?" Scott calls as his hand reaches for Allison again. It's like the kid lost all direction in his life if he wasn't hanging off her arm for at least 16 hours each day like a needy toddler. Stiles barely spares a thought for it (such things have become common practice and the entire pack was used to it by now) but Scott never, _ever_ forgets his birthday. It's not exactly as if it changes year to year.

"Nothing, we're good. Nice day, isn't it?" Stiles says, instead of the colossal tirade he was about to launch into. He would not make a fuss. He would wait for Scott to realise and then Scott could apologise and use his unfair puppy eyes and Stiles would forgive him. That's how it always goes because who could refuse actual wolf-style puppy eyes?

But, of course, people tend to notice when Stiles is quiet. Allison reaches out to touch Stiles' shoulder but he dashes off before she can touch him, yelling something about having to get to class. Punctual Stiles is almost as strange as Quiet Stiles though and he can practically hear Scott's brain panicking and flitting from explanation to explanation. He won't get it. He never does.

...

Arriving to class 10 minutes early has some definite advantages, namely that Stiles gets first pick of any seat that he wants and under the current circumstances (e.g. ignoring Scott as much as possible) Stiles decides that a seat at the back would be great... And in the corner, too. So he shuffles between rows and columns until he's sat next to the window with only the seats to his right and in front of him for Scott to take if he arrives _right now_. But as people flood in, both seats are taken and Stiles knows he's safe for the next hour.

Scott arrives at the very last minute and ends up sitting right in the middle at the front, throwing Stiles a confused, concerned look.

"McCall!" Coach Finstock slams him hand on Scott's desk with more force than strictly necessary. "Why are you still stood up, McCall?"

"Sorry, Coach, I just..." Scott tries to explain by gesturing towards Stiles, who opens his notebook and avoids eye contact with either of them.

"You just... You just what, McCall?" Finstock leans closer to Scott and stares at him, eyes widened scarily. "_Sit down_, McCall!" Scott sits, and Finstock starts talking about stocks and bonds and shares and mergers and money and... Economics. About halfway through the lesson, Scott leans over towards Greenberg and 'whispers' to him, asking what the date is.

"It's April 8th." Stiles answers before he can stop himself and the whole class turn to look at him, Finstock included.

"BILINSKI! It's great that you are slightly less of a disappointment to evolution than McCall, but maybe you could _shut the hell up in my class!_"

"Sorry Coach," Stiles mutters, refusing to look at Scott who is staring at him with a mixture of terror, embarrassment and failure on his face. _Yeah, feel bad, McCall_.

...

"Stiles."

"No."

"I'm really sorry, Stiles!"

"No."

"Listen, you know I never forget stuff like this -"

"_Almost_ never." He corrects him bitterly.

"Seriously, Stiles, I'm sorry," Scott grabs his shoulder and pulls him out of the stream of people heading down the corridor. "I should've remembered, it's just, there's a lot going on right now."

At that moment, Stiles' phone buzzes angrily in his pocket. Or maybe it just sounded angry to Stiles because he was angry. Maybe it was a happy buzz and Stiles was just too irritated to care. Either way, he yanks it out of his jeans pocket and reads it. _'Happy birthday – Derek.'_ Derek remembered? How did Derek even get his number?

"Who is it?" Scott asks, trying to grab the phone from his hand. Stiles shoots him a warning look and he stops straight away, giving him those dreaded puppy eyes. "Dude, I'm sorry. How many times can I say it?" Stiles holds his phone up in front Scott, showing him the message.

"DEREK remembered. I don't even know how he knows in the first place, but he _remembered_. You've been replaced as best friend, _sorry_." He momentarily hates himself for the mocking tone in his voice, but he gets over it pretty quick. "You've not even said happy birthday yet."

"Happy birthday!" Scott yells suddenly, throwing his arms wide and bear hugging Stiles.

"Dude, you're going to bruise me!" He tries to bat Scott off, but his hold is firm and unmoving, "I don't heal like you, I take _time_!"

"Happy birthday! I love you, I really do. You're my best friend, you're like... A really cool guy, the coolest. This will be your best birthday ever, I promise." Stiles rolled his eyes and Scott finally released him. A swift punch to Scott's arm later, and everything is forgiven... Almost. Not that he won't use it to his favour later.

...

Stiles' first impressions were right. It was a terrible, stifling day at school made only slightly better by the fact that the pack was trying their best to be nice to him. Not a single one of them had remembered and it was an awful blow to his ego, quite frankly. Once Scott had told them all, he had been ambushed by first Isaac, Boyd and Erica who decided now was a great time for a group hug with Stiles at the very centre. Isaac had been sweet, telling him that he was sorry and flashing him with puppy eyes that put Scott's to shame. He kind of ruined the moment by rubbing his blond stubble against Stiles' jaw, but the sentiment was cute. Boyd clapped him on the shoulder and made way for his louder, far more outgoing other half. Erica leapt on him and yelled that he should've said something sooner and they _'could've had a party!'_

The next to find him were Lydia, Jackson and Allison. The girls hugged him and apologised quietly, promising to make it up to him in any way they could (which had Stiles' brain dashing off on some Lydia-based tangents) and Jackson just nodded at him, wished him a happy birthday then dragged Lydia away to their next lesson.

At lunch everyone fought to sit next to him or opposite him and for once, he actually felt wanted in the pack. It was a nice feeling. He ended up sandwiched between Isaac and Erica, with Boyd on Erica's other side. Jackson, Lydia, Allison and Scott squished close on the bench opposite them and everyone seemed to be leaning towards Stiles, like he had a new gravity. Even Danny joined them, but Stiles figured that was more to do with sitting next to Isaac than celebrating with them.

By the end of the day, though, Stiles was ready to drop onto his sofa and enjoy a few hours of mindless reality TV shows. He'd been constantly touched and hugged and even sung to by the rest of the pack, which he couldn't complain about, but somehow it had all exhausted him. He planned on grabbing a can of soda, ordering take out and maybe having a Lord of the Rings marathon or something. His dad had texted him in last lesson and told him that he would be spending the evening at the station. He was sorry, but he didn't have a choice, something about another murder in town. News of another murder had piqued Stiles' interest, but not enough to worry about it now. He was tired. It was his birthday. The supernatural world could wait until tomorrow.

...

Frodo had just left The Shire when there was a loud knock at his front door.

"Yer a wizard, Stiles." He muttered to himself. It was his birthday after all; maybe this was the start of his magical career. "Or maybe someone's sent me a stripper. Or it might be food." Unsure of which he'd want first, he opened the door wide, his eyes full of hope. But he didn't smell any delicious fries, and there was no bikini-clad blonde on his doorstep.

"Sorry to disappoint." Derek said, stepping past him into the house without a pause. Of course Derek had heard his ruminations about food and strippers, werewolf hearing being what it is.

"Please, Derek, come right in." He said to the empty porch. He slammed the front door and followed Derek through to the kitchen, where Derek was standing awkwardly by the fridge with his arms crossed and his scowl slightly less prominent than usual. "What do you want?" He asked, folding his own arms across his chest.

"I came to wish you a happy birthday."

Silence descended over the kitchen as Stiles thought about his words.

"You came to say happy birthday?" He raised his eyebrows, fixing Derek with an unimpressed stare, "There are so many things wrong with that, I don't know where to start..."

"What?"

"Ok, let's start with the fact that your house isn't exactly around the corner. You drove all the way here to say happy birthday, which you've already done by text this morning, you polluted the atmosphere for that?"

"It was hardly a large amount of pollution. It's 10 minutes."

"You do know that people who live in polluted areas are 20% more likely to develop lung cancer?" Derek's expression softened and turned pitying when he realised where Stiles was going. "And personally, that's an issue quite close to my heart."

Stiles felt his throat start to go dry. Of course Derek understood what it felt like to lose someone, but he wasn't sure why he said that. Why did he bring up his dead mother when Derek only wanted to say happy birthday? It sounded like he was _blaming _Derek and his fancy car.

"I, uh..." Derek started awkwardly, "I... also wanted to give you this."

From out of his pocket, Derek drew a rectangular box, which he placed carefully on the counter top and slid towards Stiles. Stiles knew that if he were one of the betas then Derek would've thrown the box. As it was, neither of them trusted Stiles' ability to catch small objects. Or any objects, if he was honest with himself. He swiped the box off the kitchen surface and held it close to his eyes, examining each surface before speaking.

"It's a bit soon in our relationship, don't you think?" Stiles quipped. Derek's eyebrows contracted but one corner of his mouth hitched up slightly, so Stiles took that as a success. It had either been that or _'A spring wedding would really bring out your eyes.'_ Which Stiles thought might be pushing certain boundaries.

"Just open the damn box, Stiles." Derek spat at him. Stiles noticed the lack of venom though and smiled sweetly at Derek. A muscle clenched in Derek's jaw as he watched Stiles' mouth curving upwards. "Go on."

Stiles did as he was told for once and opened the damn box. Inside, nestled into soft velvet, was a chunky black Swiss Army Knife about 3 inches long and glinting in the fluorescent light. It looked as though it had about 50 different attachments from corkscrew to nail file to knife.

"Dude, this is awesome! You actually got this for me?" Stiles exclaimed before really thinking the question through.

"No, I found it at the side of the road all nicely gift wrapped." Derek replied without missing a beat. Stiles briefly thought that he should stop exposing his Alpha to his sarcasm – it was obviously rubbing off on him. He gave a fake laugh and started stroking the penknife.

"Seriously, this is so cool, it's unreal. I always wanted one of these but dad said that minors shouldn't be allowed weapons." He supposed that it was fair enough that he shouldn't have knives, given that he was the Sherriff's son, but now he was a legal adult and free to do whatever he pleased. "I'm not a minor anymore."

"No."

"Hey, I could even have sex now!" Stiles shouted with joy, grinning suggestively.

"I don't know why you're looking at me."

"I wasn't looking at you. Not like that." Then Stiles realised that Derek had basically rejected him. "Hey! Are you trying to tell me that you wouldn't tap this?" He turned around to give Derek a better view, but spun around again when Derek made a weird growling noise. They stared at each other for a moment before – "So, anyway, why a penknife, I mean, most people, you know, wouldn't, well, probably wouldn't think of that." Stiles rambled on as he grabbed a couple of plates from the cupboard and put them on the table. He'd ordered take out only for him, but if he was honest with himself there was probably enough for at least two and he'd kind of assumed that Derek would stay if offered food. Seriously, Stiles had no idea when the guy ate.

"Tradition." Derek grunted, moving out of Stiles' way when he went to get tomato sauce from the fridge. "Hale's always got one for their 18th. I thought you might want one."

_But I'm not a Hale_, Stiles thought as he carried the plates and tomato sauce through to the lounge, setting them on the floor in front of the TV. _Does this mean he's accepting me into the Hale Pack? Definitely? _

"Yeah, it's cool, awesome actually." There was another knock at the front door so Stiles collected his wallet from the kitchen and went to pay the delivery guy. When he took the pizza, chips, garlic bread and onion rings back into the lounge, Derek had made himself at home, sitting on the far end of the couch and channel surfing. He takes a deep breath.

"Smells good."

"It's still not a stripper."

Stiles laughed loudly as Derek tensed up.

...

Stiles had been right, Derek stayed with him right through The Fellowship of the Ring, despite them having no plans for him to do so. It surprised Stiles that he felt so comfortable in Derek's company and that Derek was actually _willing_ to stay, he'd never seemed like a social butterfly, or even someone who left the house unless there was some kind of supernatural apocalypse, but he stayed with Stiles right up until the credits rolled and Enya crooned away in Elvish.

Somewhere between Rivendell and Lothlorien Stiles decided to inspect his new penknife, taking out each of the attachments individually. He had started by pressing his fingers to the blade to see if it was really that sharp. It was.

"I knew that was a mistake." Derek said and he watched Stiles' mouth sucking his finger.

After that, Stiles only tested the non-sharp parts of the penknife like the nail file, magnifying glass and the little red light at one end. He'd annoyed Derek with that for about five minutes before he got a flash of red that had nothing to do with the light. Stiles muttered an apology and checked that the scissors worked by trimming a few strands of his own hair.

Once the film was over, Stiles took the empty plates to the kitchen and put them into the dishwasher. When he went back to the lounge, Derek was putting his leather jacket on and checking his cell. Even though Stiles knew that Derek had better things to do than spend his time watching fantasy movies and eating pizza, he had hoped Derek would stay for just a little longer.

"You off then?" Stiles asked, even though it was blatantly obvious that Derek was leaving. He had his shoes and jacket on and he was walking towards the door.

"Yeah, thanks for..." He gestured towards the couch and where the food had been. Stiles just nodded.

"Thanks for the penknife, it's the most awesome present I've had all day." It wasn't a lie because a) the penknife was really cool and b) he hadn't had any other presents yet. His father wasn't coming home until the early hours of the morning and Stiles hadn't seen him before school. His birthday had basically been postponed, except for Derek's visit. Even though what he'd said wasn't a lie, there was still a part of Stiles that felt guilty for having said it, like he wasn't telling the entire truth.

When Derek was stood on the porch again, he turned to face Stiles.

"Listen, I know Scott forgot about today, but there has been a lot going on..." Even as he said it, he looking a bit pissed off. Stiles wasn't sure if he was annoyed at Scott or... Something else.

"I know. I'll get him to make it up to me somehow."

"Good." Derek mumbled as he turned and walked towards his car. Stiles followed him out and stood on the porch to wave goodbye. It was well and truly dark outside, but the streetlamps were giving off enough light that he could see Derek unlocking his car, climbing in and driving away.

He went back inside and put the DVD back in its case, then returned the case to its rightful place on the shelf. When everything was in order downstairs, he grabbed his cell phone and his new penknife and climbed the stairs to bed, yawning as he flopped onto his mattress. He hadn't even realised he'd been so tired, but now he wanted to sleep for a few months. Things at school were only going to get harder, too, what with the summer exams coming up. He wished it would all go away.

"Ahem." The sound of someone clearing their throat by his window broke the silence and Stiles flipped over, sitting up like a bolt. Derek smirked. Jackass. Stiles lay back down, propping himself up on his elbows.

"Did you forget something?" Stiles asked, rubbing at his neck with his right hand. Derek's glittering eyes followed the movement intently then drifted up and down Stiles' body sprawled on the bed.

"Actually... I think I did."

...

He was slowly advancing on Stiles, staring into his eyes the entire time as he took off his jacket and dropped it to the floor. _I'm going to die,_ Stiles thought as he watched wide-eyed as this handsome, brooding man carefully climbed on top of him, holding his weight on his knees and forearms so he didn't squash the deliciously fragile body beneath him.

Stiles' heart beat had gone through the roof and he was struggling to get enough oxygen with each breath. As much as he tried to hide it, he knew Derek could hear the effect he was having. Not only was he listening to it, but he was enjoying it too; he was enjoying seeing Stiles going to pieces without even touching him.

Derek dropped his mouth to Stiles' neck and brushed his lips on the pulse point there. He barely even made contact, but it made Stiles let out a light, breathy moan. That noise did things to Derek that Stiles could barely imagine. The noises in the room only intensified as Derek ravaged the pale skin of his neck, leaving a trail of marks that identified Stiles as _his_.

"_Mine._" Derek growled as he gripped the hem of Stiles' shirt and lifted it off him in a smooth, practiced motion. Even when he was unravelling, Stiles was very stubborn. Even as he was shuddering and groaning with what was happening to him, he refused to let Derek stay fully clothed, tugging at his T-shirt until Derek leant back and tossed it across the room. Then Stiles went for his belt. With a huge mind-over-matter effort, Derek pulled away slightly. Everything in his was screaming at him to _take_ - to take what Stiles had. "Stiles."

"Hmm?"

"Are you sure about this?" Derek asked him seriously.

"Hell yeah." He answered straight away, running his finger up to Derek's chest and back down. There wasn't a single blip in his heartbeat. Derek's belt and trousers soon joined the rest of their clothes on the floor.

...

"That," Stiles said afterwards, "Was the best birthday present I've had in a long time."

He was lying on his back next to Derek, who was on his side. There were tangled together in a heap of limbs and hands and feet and... Other appendages. Derek was looking at him hazily, his eyes partially closed and his lips quirked at one corner.

"I've been waiting two years to do that." He said vaguely. Stiles' mind was thrown into overdrive. He could've been having this for the last two years? Why exactly hadn't he? "I wanted to wait until you were 18. It was a close call though... I just wanted to..."

"You just wanted to tap my fine ass, I know."

"It was more than that." He muttered, taking Stiles' hand in his and lifting it to his mouth. "It's always been about more than sex. Although that was fantastic..."

"You're telling me?"

"You're brave," Derek continued as if uninterrupted, "Selfless. You fight for those you love." Stiles watched blankly as Derek kissed and then nuzzled his hand, pressing it against his cheek and sighing contentedly. "You smell good too, like pack and me and... Sex. It's hot." His breath hitched again, why could a simple sentence turn him on so much? "And there's one other thing..."

"What's that?"

He leant over until he was whispering right against Stiles' mouth.

"You have an irresistibly fine ass."

_Happy birthday, Siobhan!_


End file.
